Yanmar Type C panel starter switch voltage

[TheOffice]

I've got a Type C panel and a 4JHTE. the starter switch key is the round type.

What is the voltage supposed to read from the terminal coming out of the switch to power the panel when the engine is running.

I'm getting a reading of 1.7 volts and my tach is not working. (Replaced the sender, so I can rule that out). Thought it was 12 volts?

[donradcliffe]

Likely a wiring problem. Curious how you started the engine.

The key switch should have one terminal which reads 12v all the time. There should be also be two terminals that get energized depending on switch position. The first is the 'ignition', which should activate the voltage regulator and the low oil pressure alarm. The second is the starter, which activates the starter solenoid either directly or through a relay.

Do you have any alternator output? Many tachs are alternator driven, and the voltage regulator gets turned on by the ignition switch.

[TheOffice]

The tach has a flywheel sensor. Alternator is working, so the exciter wire is good. Should the terminal be putting out 12 volts?

[donradcliffe]

typical switch wiring

[Redline452]

There are a number of connectors in the wiring harness from engine to panel, any one of which can contribute to a voltage drop. My panel has three sets of connections on series (transition between plug types, apparently), plus an extension in the aft cabin and the plugs at the engine. Check/clean the entire run.
In the end I added a cube relay at the starter instead of relying on the harness to deliver full voltage to the solenoid. If it clicks but does not crank, you have too much voltage drop for the solenoid to engage fully - needs at least 10-21 volts.

[Wernito]

Originally Posted by TheOffice

I've got a Type C panel and a 4JHTE. the starter switch key is the round type.

What is the voltage supposed to read from the terminal coming out of the switch to power the panel when the engine is running.

I'm getting a reading of 1.7 volts and my tach is not working. (Replaced the sender, so I can rule that out). Thought it was 12 volts?

I have the same engine and sometimes in Winter or after a rainy season my tach will not show but eng runs fine. Acording to yanmar it is humidity in the panel and nothing to worry; you can blow the panel dry if needed

[TheOffice]

Don thanks for the diagram.
Engine has a relay and starts great. Problem is power at the panel. 12 volts into the switch but only 1.7 v out. Looks like a bad switch.

[Wotname]

Originally Posted by TheOffice

Don thanks for the diagram.
Engine has a relay and starts great. Problem is power at the panel. 12 volts into the switch but only 1.7 v out. Looks like a bad switch.

Yes, it does!